SAN JUAN, Puerto Rico — The worst drought in five years is creeping across the Caribbean, prompting officials around the region to brace for a bone-dry summer.

From Puerto Rico to Cuba to the eastern Caribbean island of St. Lucia, crops are withering, reservoirs are drying up and cattle are dying while forecasters worry that the situation could only grow worse in the coming months.

Thanks to El Niño, a warming of the tropical Pacific that affects global weather, forecasters expect the hurricane season that began in June to be quieter than normal, with a shorter period of rains. That means less water to help refill Puerto Rico’s thirsty Carraizo and La Plata reservoirs as well as the La Plata river in the central island community of Naranjito. A tropical disturbance that hit the U.S. territory on Monday did not fill up those reservoirs as officials had anticipated.

Puerto Rico is among the Caribbean islands worst hit by the water shortage, with more than 1.5 million people affected by the drought so far, the U.S. National Drought Mitigation Center says. The amount of water flowing into 12 of at least 22 rivers that supply the island’s reservoirs is at an all-time historic low, the Department of Natural Resources reported Wednesday.